The term “claw rotor” designates a rotor of a rotary electrical machines, the poles of which are in the form of claws. A rotor of this type is composed of two opposite imbricated magnet wheels, each comprising claws. Each claw of a magnet wheel extends in the direction of the other magnet wheel, and is inserted between two consecutive claws of the opposite magnet wheel. The claw rotor comprises magnetised parts, and the excitation winding is wound around the rotational shaft of the machine.
The rotor is arranged inside a stator. When the rotary electrical machine is functioning, the rotor rotates around its axis, and the magnetic flux circulates between the adjacent magnetic poles with respective opposite polarities, passing via the windings of the stator. The magnets disposed between the magnetic poles constituted by the claws are used to prevent the magnetic flux from passing directly from one pole to the other, without passing via the stator.
Document FR 2 932 325 describes an electrical machine which is particularly suitable for motor vehicles, provided with a claw rotor with interpolar magnetic assemblies comprising magnets, which have both a reduced size, and are secured in lateral grooves in the polar claws. Document FR 2 818 823 describes a means for producing the winding of the excitation winding of a claw rotor.
Generally, fans are fitted around the rotational shaft on both sides of the magnet wheels, in order to cool the winding.
The excitation winding of a claw rotor comprises two end wires connected to collector rings, on which brushes rub in order to supply the excitation winding. Each end wire is bent at the top of the winding, and passes through a radial cavity provided between a wall of a magnet wheel and a recess in the fan, and an axial cavity provided between the shaft and a recess in the fan.
During functioning of the rotary electrical machine, the end wire is subjected to substantial vibrations which give rise to premature breakage of the wire at the bend.